The security update may prevent you from opening CHM files that you downloaded from the Internet, even if you saved them to your local hard disk.
How to resolve?
To resolve this problem, clear the “Always ask before opening this file” check box in the Open File-Security Warning dialog box, and then click Open.
If you click Open without clearing the checkbox, the help file’s table of contents will appear, but the body text will not.
It took me some time to figure it out. Hence I am putting it up for my fellow mates to make things easier.
